1. Field of the Invention
Embodiments according to the invention relate to a method and apparatus for frame mirroring in a network environment. More particularly, embodiments according to the invention relate to mirroring frames to a diagnostic system not connected to the device performing the mirror operation.
2. Description of the Related Art
Effectively deploying multiple devices in a network environment becomes an increasingly complex task as transmission data rates, processor speeds, and storage capacities increase. Storage area networks (SANs) have been developed as specialized high-speed networks, referred to as fabrics, to connect computer systems, control software, and storage devices over the fabric. A SAN typically allows block level input/output (I/O) rather than file-level access. Thus, every device connected to a SAN fabric appears as a locally attached device to other devices on the fabric.
Data rates of the switches which form the SAN are currently very high, such as 8 Gbps. At these rates diagnostics become very difficult. This makes simple trace capture inside the switch difficult as the needed memory could easily exceed that needed for normal switch operations. Protocol analyzers are readily available, but their operation commonly requires that they be connected in series with the input or output port being tested. This makes connection of a conventional protocol analyzer troublesome in many instances. One approach that has been used to alleviate this problem is to mirror selected frames to a designated port connected to a diagnostic system. However, this approach has been limited because of a requirement that the diagnostic system be directly connected to the switch performing the mirroring. In a practical sense this meant that the diagnostic system had to be connected to either the same switch as the frame source or the frame destination. While better than being required to be in series, this direct connection requirement still limited the flexibility of the SAN configuration unduly, requiring reconfiguration should the diagnostic system not be connected to one of the necessary switches, assuming that the switches can perform the mirror approach.